Answer: B. The jeweler does a calculation to find the number of beads he needs and compares the amount to 19,000.
Step-by-step explanation: The jeweler is calculating the number of beads he needs by multiplying 48 beads per set by 400 sets. This calculation helps him determine the total number of beads required. By comparing the result, which is 19,200, to the amount of 19,000, the jeweler can support his conclusion about the number of beads needed.